Retinal tears can occur when the vitreous, a clear gel-like substance that fills the center of the eye, pulls away from the retina thereby leaving behind a tear or hole in the retina. Rhegmatogenous retinal detachments can result if the retinal breaks (i.e., tears or holes in the retina) are not treated. With retinal breaks, fluid from the vitreous apparently seeps through the retinal break and accumulates under the retina. The degree of detachment is measured by the volume of subretinal fluid present as well as the area of the retina involved. Some symptoms of retinal detachment include the presence of floaters, flashes, shadows or blind areas, decreased visual acuity and metamorphopsia.
A number of techniques may be employed for treating retinal detachments, including using a scleral buckle, pneumatic retinopexy, cryopexy (i.e., freezing) and photocoagulation using a laser or xenon arc light source. These techniques may be used alone or in combination with each other to treat the retinal detachments. For example, a combination of a scleral buckle and photocoagulation may be used in some cases. Alternatively, retinal tears with little or no nearby detachment may be treated using photocoagulation or cryopexy.
Current vitreoretinal techniques in which surgical instruments are inserted into the eye require the dissection of the conjunctiva 4 and the creation of pars plana scleral incisions through the sclera 6. As more clearly illustrated in FIG. 1, the dissection of the conjunctiva typically involves pulling back the conjunctiva 4 about the eye 2 so as to expose large areas of the sclera 6 and the clipping or securing of the conjunctiva in that pulled back state (normal position of conjunctiva shown in phantom). In other words, the sclera 6 is not exposed only in the areas where the pars plana scleral incisions are to be made. As discussed below the area of the sclera 6 through which the infusion cannula would be inserted also would be exposed.
Following the creation of the incisions, surgical instruments are passed through these incisions and the inserted instruments are observed through the pupil using a microscope and corrective optics. These instruments are used to manipulate and/or dissect retinal tissues within the eye as well as to implement the specific retinal treatment technique (e.g., photocoagulation). The scleral incisions created for vitreoretinal surgery are made large enough to accommodate the required instruments, the inserted portions being typically 19 or 20 gauge (approximately 1 mm) in diameter.
For example, using a laser in the photocoagulation technique, an instrument capable of transmitting bursts of laser light is inserted into the eye and the retinal break is surrounded with one or more rows of a plurality of laser burns or laser heat spots. These laser burns or heat spots produce scars which prevent fluid from passing through and collecting under the retina. In the photocoagulation procedure, a gas is exchanged with the vitreous fluid being aspirated from within the eye so that the gas is intraocular when performing photocoagulation.
During vitreoretinal surgery, intraocular pressure is maintained by infusing a fluid, such as a buffered saline solution, from an elevated IV bottle into the eye through a cannula. Often the surgical procedures will call for air to be infused through the cannula while the fluid is being drained and/or aspirated through a second port or means. Such a cannula also is passed through an incision or is inserted through the sclera 6 by a trocar.
After completing the specific treatment procedure, the inserted instruments are removed from the incisions in the sclera. Because the incisions through the sclera are large enough to pass 19 or 20 gauge instruments, the incisions are typically too large to self-seal. Thus, the incisions must be sutured shut. Similarly, the infusion cannula is removed from the sclera and the opening or incision in the sclera 6 for the cannula also is sutured shut. Following the suturing of the scleral incisions, the surgical personnel reposition the conjunctiva in its normal position and reattach the free end(s) of the conjunctiva to the eye 2 using sutures.
While such methods and techniques have proven to be effective in the treatment of vitreoretinal disease, there is a strong motivation to move away from procedures requiring sutures and instead look to greatly simplified sutureless procedures. Thus, it would be desirable to have improved and novel methods to perform such sutureless procedures that would be simpler as compared to prior art methods or techniques as well as to provide improved surgical instruments that are useable during such sutureless procedures and which preferably would be no more difficult to use than existing prior art devices. Such sutureless procedures would preferably be less costly and less intrusive as compared to prior art procedures.